Background: One of the main causes of neurological issues is still brain tumors. The age-standardized incidence of malignancies of the central nervous system rose 17.3% between 1990 and 2016. The present study was conducted to assess role of perfusion MRI in evaluation of brain tumours by using relative Cerebral Blood Volume (r CBV). Materials & Methods: 43 cases of brain tumour of both genders was selected. MRI was performed on 23 patients using conventional imaging, perfusion imaging with T2*-weighted Echo-Planar sequence after administration of Gadopentetate dimeglumine. Perfusion data was processed to obtain colour maps and rCBV value was generated. rCBV values were correlated with histopathological grade of tumours. Results: Out of 43 patients, 23 were males and 20 were females. Common brain tumor was astrocytoma in 30 and medulloblastoma in 13. Grade was grade I in 10, grade II in 21, grade III in 7 and grade IV in 5 cases. The difference was significant (P< 0.05). The mean relative Cerebral Blood Volume (rCBV) in grade I was 2.5, in grade II was 4.6, in grade III was 8.1 and grade IV was 13.7. The difference was significant (P< 0.05). Conclusion: Prior to surgery, perfusion MRI can be used to distinguish between low-grade and high-grade gliomas. Therefore, its incorporation into standard MRI will improve the diagnostic precision in distinguishing between low-grade and high-grade gliomas.